This invention relates to a storage system connected to a host computer via a channel, and more particularly, to a technology for controlling the channel by a plurality of processors.
In recent years, there are many cases where a single large-scale storage replaces a plurality of storage systems. Moreover, there has been employed a technology for making a plurality of storage systems recognized as a single large-scale storage system. These technologies facilitate management of the storage system. In these cases, the large-scale storage system is required to achieve higher performance as well as an increase in storage capacity.
On the other hand, there exists a need for extending an inexpensive small-scale storage system to a large-scale storage system.
As technologies to support the extension of the system from small scale to large scale, there have been known a virtualization switch technology and a highly scalable technology.
For example, the virtualization switch technology is disclosed in U.S. Pat. No. 6,898,670. According to the virtualization switch technology, a SAN switch which constitutes a SAN (Storage Area Network) provides a virtualization function. Specifically, the virtualization switch technology provides a host computer with a plurality of storage systems connected the virtualization switch as a signal storage system. Moreover, the virtualization switch provides various functions to the plurality of storage systems connected to the virtualization switch.
In this case, however, an administrator has to respectively perform settings for the virtualization switch and the plurality of storage systems. Moreover, a conversion process for the virtualization carried out by the virtualization switch becomes a bottleneck in performance of the storage system.
The highly scalable technology of the storage system is disclosed in JP 2004-240949 A. A highly scalable storage system includes a large number of processors for controlling the highly scalable storage system. Moreover, the highly scalable storage system includes a large number of protocol processors.
The protocol processor is disclosed in U.S. Pat. No. 6,791,989. The protocol processor processes a protocol of a channel for connecting a host computer and a storage system to each other. Specifically, the protocol processor converts a protocol of a packet or a frame received via the channel into an internal protocol of the storage system.
When the storage system is highly scalable, the storage system can be extended from a small-scale configuration to a large-scale configuration. Accordingly, it is possible to provide a storage system according to a scale requested by a user.